[mail]

I replaced a radiator and valves and had to drain down the system. I refilled the system and vented the rads but the heating is not working. The boiler fires up and heats the water to a certain temperature then cuts out. The pump is working and I have opened the screw on the pump to release air there. The pipe at the top of the hot water cylinder is hot while the return at the bottom is cold. There is a air release valve at the top pipe of the cylinder and I have vented this also. I also opened the drain valve at the boiler and let the water run through a while to try and clear any air in the pipework. It seems there is an airlock somewhere within the pipework which is not letting the water circulate within the system. Can anybody give me some advice as to how I can clear it. I am baffeled as to how air can stop water circulating , thanks in advance for any advice.

[spireland32]

You have numerous threads on heating and plumbing problems.... You get so far and get stuck then look for help. If you don't know what you doing leave it to a professional.

[anthonyos]

EXPERIENCE is what your looking for in this situation not try this and try that

[mail]

Yes I have a lot of questions about plumbing, the fact is my plumbing is over 25yrs old and in need of a refit, but unemployed at the moment and trying to keep it going, not trying to be a plumber. When my fortunes turn around I will have a Plumber refit a whole new system, until then I will try and fix it myself. If you want to give me advice on plumbing I will be very grateful, if not, please dont give me a lecture. Are you more interested in reading my past queries or giving advice? If you dont want to give advice why not read other peoples posts instead. I have had great help on here from people and have resolved a lot of problems. Is this forum only for plumbers ? if so I am sorry for accessing it, as I am DEFINATELY not a Plumber, just trying to keep the system going, thanks.

[Billy Bunting]

Hi Mail, I don't think anyone is being rude here its just that its very difficult one to answer as all systems are diferent and unless we are actually there and can see the system then its just a guessing game.
It sounds like the cylinder flow and return are circulating so have you tried turning off some of the rads and trying to pump the air lock, you could also try closing the lockshield on the return from the cylinder to give the pump a bit more humph.

[shane0007]

It will depend on where the air lock is located. Try you isolate where it is and perhaps crack open a joint to release the air. You only have to loosen the nut enough to pull back the pipe without completely pulling them apart.

I had a three storey system that air-locked that nothing would seem to shift it. I connected the garden hose to the boiler drain valve, it blew the water through the vent pipe which cleared the air lock.
Anoth